Conventionally, rubber compositions containing an ethylene-α-olefin copolymer, and heat-resistant belts using a rubber composition containing an ethylene-α-olefin copolymer and an ethylene-α-olefin-diene copolymer have been proposed (e.g. refer to Japanese Patent Nos. 3951415B and 3911840B, and also Japanese Unexamined Patent Application Publication Nos. H11-292236A and 562-205910A).
As raw materials for these heat-resistant belts, EPM (ethylene-propylene copolymer) exhibits low productivity, and supply of EPDM (ethylene-propylene-diene copolymer) has been unstable since demands for EPDM increases when the market is active and exceeds the supply thereof.
However, heat-resistant belts obtained by using a rubber composition containing an ethylene-α-olefin copolymer exhibit poor physical properties, such as low elongation at break (EB) in a normal state, low elongation at break (EB) after aging, and low tensile strength (TB).
Furthermore, rubber compositions for heat-resistant conveyor belts that can replace conventional raw materials are needed from the perspective of supply conditions of EPDM. The rubber composition for heat-resistant conveyor belts that replaces conventional products is desired to exhibit the same or superior heat resistance and processability compared to conventional products.